SPO 1862, 351 W, was delivered with a 160' thermostat. Water temps met the 160 level;
oil generally ran around 140-150' when ambient temperatures ranged from 70-80'. I replaced the thermostat with a unit rated to 180'. At the same air temps, the
oil would usually get as hot as 200' but more commonly runs 165'-170.' When air temps exceed 100', the
oil maintains 190'. Oil temps will exceed 200' but only while the car is being driver hard - 4800-6200 RPM; oil temp quickly returns to 190 at sustained 2900-3200 RPM.
The oil cooler is not connected. I use 15-50 Mobil One and an 8 quart capacity sump.